Jo Dunkley combines her expertise as an astrophysicist with her talents as a teacher and writer in Our Universe: An Astronomer’s Guide, a lively and exceptionally clear introduction to the structure and history of the universe and its enduring mysteries. We spoke with her about the book and her seemingly limitless topic.
Needless to say, the universe is a big subject. How do you even start to explain something so vast?
The universe is really big but it turns out that it fits together in a pretty well-organized way, with planets around stars, collections of stars making up galaxies, then galaxies filling the bigger space around us. So I start here on Earth and move gradually out to the farther reaches of the universe, scaling down larger and larger sizes into manageable spaces like basketball courts that are easier to visualize. I also connect the big concepts to real people, telling the stories of the astronomers who have made, or are still making, our discoveries.
The book conveys the kind of wonder about astronomy that draws us to the stars as children. Is it easy to keep that kind of wonder in your daily work as you wrestle with cutting-edge technical debates?
Not always, no. I do often get sidetracked by the technical details of analyzing data. But that’s one of the reasons I love writing about my science for the general public—and talking about it, too. It reminds me of the bigger picture and brings back my wonder. And even in my daily research I do get regular reminders about how exciting the questions are that we are asking. For example, right now I am trying to work out how fast the whole of space is growing. There are a lot of technical challenges to doing that, but I love the fact that we can even ask this question.
Many of us who haven’t taken science courses since high school assume astronomy can’t possibly be for us. We think we’d get lost. Is it a subject that can or ought to appeal to those who don’t think of ourselves as scientific?
Absolutely. You don’t need difficult math or complex science to grasp the big ideas in astronomy and to appreciate how beautiful the universe is. Looking up to the skies and asking questions about what’s up there is something humans have been doing for millennia. It is a subject for all of us.
The book makes it clear that we have a lot left to learn about the universe. What are some of the questions that you think are the most pressing or the most promising to pursue in the years ahead?
One very exciting question is how common planets like ours are in the universe: rocky planets that could perhaps host life. New telescopes will help enormously with that question. And we have found out that most of the universe is made of invisible stuff that we can’t see with our telescopes. We call it dark matter, and there seems to be much more of it than the normal atoms that we are made of. We suspect that it is a new type of particle as-yet unknown in nature. I hope we will soon find out!
The book features many of the great names we would expect to see—the Galileos and Einsteins—but you also draw attention to unheralded and underappreciated astronomers, many of them women. Is it fair to say that some of the lost remarkable work done over the past 100 years has been done by women, either as individuals or in teams, like the Harvard Computers?
They have had a huge impact. The Harvard Computers in the early twentieth century, including Annie Jump Cannon, Henrietta Swan Leavitt, and later Cecilia Payne-Gaposchkin, were responsible for making sense of the different types of stars, understanding how to measure vast distances in the universe, and figuring out what stars are actually made of. Other pioneering women include Vera Rubin, who solidified the evidence for invisible dark matter, and Jocelyn Bell Burnell. She discovered an entirely new type of spinning star that is so dense that a teaspoonful would weigh as much as a mountain.
